DataStax Astra DB: SHRED_BAD_VECTOR_SIZE / dimension mismatch after model switch

TL;DR

The fix is to delete the collection in the Astra DB Data Explorer and re-create it with the correct dimension, then re-seed. Astra DB collections pin the vector dimension at creation time, so switching embedding models (for example 1024-dim to 768-dim) breaks the collection.

Fix

1. The fix is to delete the collection in the Astra DB Data Explorer and re-create it with the correct dimension, then re-seed. Expected: You get the expected result; the problem is gone.

When to use

• You are setting up or using this DataStax Astra DB feature.
• The symptom matches: SHREDBADVECTOR_SIZE / dimension mismatch after model switch.

When NOT to use

• Unrelated DataStax Astra DB issues (different feature, different failure).
• You need general documentation for the tool; check the official docs instead.

Compatibility

Reported against DataStax Astra DB. Source: https://github.com/abhinavjd7/chatbotrc.

Variant phrasings

SHREDBADVECTOR_SIZE / dimension mismatch after model switch

Why it happens

Inserts or vector searches fail with a vector dimension error. The collection was created with a different vector dimension than the embedding model now produces.

Edge cases

• If your error message differs even slightly, this is probably a different issue; search the exact text.
• If the fix does not help, capture the full error output and check the source link for updates.

Source

https://github.com/abhinavjd7/chatbotrc

Source: Inserts or vector searches fail with a vector dimension error. The collection was created with a different vector dimension than the embedding model now produces.

Verified resolution: [field troubleshooting]: Astra DB collections pin the vector dimension at creation time, so switching embedding models (for example 1024-dim to 768-dim) breaks the collection. The fix is to delete the collection in the Astra DB Data Explorer and re-create it with the correct dimension, then re-seed. Watch for $vector value can't be empty and SHREDBADVECTOR_SIZE as the signature errors. Also verify the app token starts with AstraCS, the DB is Active, and the token has Database Administrator role when you hit auth failures at the same time.

Source URL: https://github.com/abhinavjd7/chatbotrc